Different behaviour from grep/ag with -o and multiple matches

[passcod]

With grep:

$ echo '50k + 1k + 11k + 37k + 18k' | grep -Po '[\d.]+'
50
1
11
37
18

With The Silver Searcher:

$ echo '50k + 1k + 11k + 37k + 18k' | ag -o '[\d.]+'
50
1
11
37
18

With ripgrep:

$ echo '50k + 1k + 11k + 37k + 18k' | rg -o '[\d.]+'
50
50
50
50
50

$ rg -V
ripgrep 0.5.1

[BurntSushi]

I think this is a dupe of #451, which is fixed on master.